Fluid pressure intensifier



Dec. 7, 1943.

W. R. TUCKER ET AL FLUID PRESSURE INTENSIFIER Filed oct. Ae, 1941 tig ?atented ec. 7,

PT lf Price Development flor-poration, lino., Wilmington, Del., a corporation of Delaware Application Dctober 6, 1941, Serial No. 413,766

(Cl. S- 52) This inventionrelates to intensiiers and, in particular, to intensiers for boosting the pressure output of :duid pressure sources as, for ln= stance, pumps.

It san object of the invention to provide intensiers which may he used in connection with pumps for boosting the pressure delivered by the latter, without imposing any material changes uponthe ilow characteristics of the pumps.

It is another object of the invention to provide intensier means which will make it-pos sible selectively to use the duid delivered by a pressure iluid sourceat its actual delivery pressure or to boost the pressure while maintaining a substantially continuous flow of the thus treated pressure uid.

A further object of the invention consists in the provision or' intensifier means in connection with a fluid pressure source, in which the operation of the intensier means is controlled by nuid pressure established by the fluid pressure source.

Still another object of the invention consists in the provision of an intensifier for boosting the pressure of a duid pressure source, in which the intensifier comprises at least two operatively connected diierential pistons.

It is a still further object to provide an intensier system for increasing the pressure of a fluid pressure pump, in which hydraulic connection oi the said uid pressure pump with a plurality of dierential pistons is controlled by a common distributing valve in accordance with the movement of said dierential pistons.

These and other objects and advantages of the invention will appear more clearly from the following specication in connection with the accompanying drawing, in which:

Figure 1 diagrammatically illustrates an intensiiier according to the invention in connection with a variable delivery pump in a hydraulic circuit.

Figure 2 is a diagrammatic illustration of an intensifier system similar to that of Figure l, but with a modified intensifier control.

General arrangement The intensier according to the invention substantially comprises a plurality of differential pistons which are so arranged in a hydraulic circuit comprising a pump, the pressure of which is to be boosted, that the said pistons automatically st rt their intensifying or boosting action as soon as the pump has established a predetermined pressure.

According to the first and second embodiments of the invention, the reversing control of the intensier pistons is effected by a plurality of re ciprocatory valves.

Structural arrangement Referring now to the drawing in detail and, in particular, to the arrangements of Figures 1 and 2, the system shown in the said figures comprises a variable delivery pump with servo-motor means which,` at the establishment of a predetermined pressure at the pressure side of the pump' i, movesl the latter to neutral or substany tially no delivery position. Such pumps are well known to those skilled in the art and may, for instance, be of the same type as the pump described in Patent No. 2,039,893 to Ernst.

One side of the pump I is connected With a uid reservoir or tank 2 through the suction linel 3. The tank 2 is adapted to communicate through conduit l with a four-way valve 5, which may be of a standard type. The four-way valve 5 communicates with a conduit t having two branches, of which the line 'l leads to the right side of the intensifier cylinder While the branch line t comprising a check valve it leads to the right side of the intensifier cylinder li. Similarly, a conduit i2 connected to the four- Way valve 5 has two branch lines i3 and lil, of which the line i3 comprising a, check valve i5 leads to the left end of the intensifier cylinder S, Whereas the line lll leads to the left end of the intensifier cylinder -l l. l

Reciprocably mounted in the intensier cylinders d and il are dilierential pistons it and il respectively, which are operatively intercom-- nected by a piston rod i3. Hydraulically connected with the smaller piston areas of the intensier pistons I6 and il are' conduits i9 and 20 with check valves 2l and 22 respectively, which conduits i9 and 2t are in hydraulic communication through conduit 23 with a four-way valve '24 adapted to direct the control of pressure iluid tween conduit 32 leading tothe four-way valve 5 and conduit 33 leading to shift valve 34 as soon as a predetermined pressure has been established in conduit 30. Such pressure controlled valves are well known in the art and for a more detailed description thereof reference may be had to Patent No. 2,086,295 to Ernst.

The conduit 33 also comprises a shutoff valve 35 which, when closed, enables operation of the piston 28 at the delivery pressure of the flu-id delivered by pump I, whereas when valve 35 is open the piston 28 will automatically be operated at an intensified pressure as created by the intensier cylinder-piston-assembly 8, I6; II, II.

The shift valve 34 is mechanically connected to the piston rod I8 so that, at the end of the strokes of pistons I6 and Il in one direction, the shift valve 34 causes fluid delivered by pump I through lines 36, 32 and 33 to flow through conduit 3'I for shifting the four-way valve 5 in one direction, whereas at the end of the strokes of pistons I6 and II in the opposite direction, fluid delivered by the pump I will pass through conduit 38 to the four-way valve 5 to shift the latter in the opposite direction. The shift valve 34 is furthermore connected through conduit 39 with the fluid tank 2. l

The intensifier system of Figure 2 differs from that of Figure 1 primarily in that the four-way valve 5 is electrically shifted instead of being hydraulically shifted as in Figure 1. To this end, the piston rod I8 of Figure 2 is provided with a switch actuating arm 40 adapted, at one end position of the pistons I6 and I'I, to actuate a switch 4I for closing an energizing circuit comprising the main supply line 42, lines 43 and 44, switch 4I, line 45, coil 46, line 41 and main supply line 48. Energization of the coil 46 causes movement of the armature 49 connected to the valve member of valve 5 toward the left.

When the pistons I6 and II have reached their other end position, the switch actuating arm 40 closes the switch 50 so as to energize the solenoid 5I, which causes rightward movement of the armature 52 and the valve member of the fourway Valve 5. The energizing circuit for solenoid 5I comprises the main supply line 42, line 53, switch 50, line 54, solenoid 5I, line 4`I and main supply line 48.

The four-way valve 5 communicates through conduit 55 with the tank 2 and through conduit 56 with a pressure controlled valve 51 similar to the valve 3l of Figure 1. 'Ihe valve '51 is connected with. a conduit 58 comprising a shutoff valve 59 performing the same function as the shutoff valve 35 in Figure 1, and connected with the pressure line 60 of pump I. The pressure line 68 comprises a check valve 6I and leads to conduit 23. Branching off from conduit 60 is a pilot line 62 connected to the valve 5I`and performing the same function as line 30 in Figure 1.

Operation of first and second embodiments Referring first to Figure 1 and supposing that the pump I is running and it is desired to operate the piston 28 at intensified pressure, the operatozi` opens the valve 35, and assuming that piston 28 is in its uppermost position, shifts the valve 24 so as to effect hydraulic communication between conduits 23 and 25. Fluid pressure delivered by pump I then passes through conduit 36. line 32, valve 5 and either conduit 6 or I2 and, consequently, either check valve I0 or I5 to the left portion of intensifier cylinder 8, or right portion of intensifier cylinder II to conduit 23 and from there through the four-way valve 24 and conduit 25 into the upper portion of the cylinder 26 so as to move the piston 28 downwardly.

If the piston 28 moves downwardly by gravity, the fluid entering the upper portion of the cylinder 26 merely fills the increasing space. The uid expelled from the lower part of cylinder 26 passes through conduit 2I,v four-way valve 24 and conduits 29 and 4 to the tank 2. As soon as the piston 28 encounters resistance exerted by a work piece, for instance, when the piston 28 has reached the position shown in Figure 1, pressure starts to build up in the upper portion of cylinder 26 and is conveyed through conduit 25, four-way valve 24 and conduitl 23 to conduit 36, causing check Valves 2I and 22 to close and acting upon valve 3| so as to effect hydraulic communication between conduits 32 and 33.

Fluid pressure delivered by pump I then passes from conduit 36 through conduits 32 and 33, shift valve 34 and conduit 38 to the four-way valve 5, shifting the latter so as to establish hydraulic connectionbetween conduit 32 and conduit I2,'if the valve 5 should not already be in the said position. Pressure will then build up in the left portion of cylinder I I and the left portion of cylinder 8 and; due to the difference in areas on both sides of pistons I6 and II respectively, the pistons I6 and I 'I will move toward the right, pressing the fluid through conduit 20 and check valve 22 into conduit 23 at an increased pressure, and the thus`boosted pressure is conveyed through four-Way valve 24 and conduit 25 into the upper portion of cylinder 26 where it actuates the piston 28 at increased pressure.

The fluid expelled from the lower portion of cylinder 2'6 is exhausted to tank 2 in the-manner described above.

The increasing space on the left side of piston I6, during its rightward stroke, is filled with fluid passing through conduit I2, check valve I5 and conduit I3, whereas the fluid expelled during this rightward stroke by piston I6 from theright portion of cylinder 8 passes through conduits 'I and 6, four-way valve 5 and conduit 4 to the tank 2.

When the pistons I6 and I'I have reached the end of their rightward stroke, the piston rod I8, due to its operative connection with the shift valve 34, shifts the latter into opposite direction so as to eifecthydraulic communication between the conduit 33 and the conduit 31. This in turn causes hydraulic shifting movement of the fourway valve 5 so as to establish hydraulic communication between the conduits 32 and 6.

Pressure fluid delivered by pump I then passes through conduits 36 and 32 to conduit 6. From here part of the fluid passes into the right portion of cylinder 8 and another part into the right portion of cylinder II. Due to the differential pressure areas of the pistons I6 and I1 respectively, the said pistons now move toward the left so that fluid is expelled from the left portion of cylinder 8 by piston I6 at an increased pressure, and passes through conduit 23, four-way valve 24 and conduit 25 into the upper portion of cylinder 26 acting upon piston 28 so as to move the latter in the same direction as previously. The fluid expelled from the left portion of cylinder I I passes through conduit I2, valve 5 and conduit 4 into the tank 2. When the pistons I6 and I1 have again reached their lefty end position, the piston rod I8 again shifts the shift valve 34 in the manner previously described and the delivery of boosted pressure fluid to conduit 23 continues.

When the piston 28 has reached the end of its downward stroke, so that a predetermined pressure is established in the upper portion of cylindervZS, this pressure will be conveyed through the intensifier proper, four-way valve 5, conduit 32 and conduits 33 and 63 to the servomotor of pump l so as to shift the latter to neutral or substantially no delivery position. The piston 2li is then held in its lower position at a predetermined pressure.

If an upward stroke of piston 2&3 at boosted pressure is now desired, all that it is necessary to do is to shift the valve 2d so as to establish hydraulic connection between the conduits E3 and 2l, while establishing hydraulic communication between the conduits 25 and 2S. then again move to delivery position and lift the piston E8 at its actual delivery pressure if no resistance is encountered by piston 28. If resistance is encountered by piston 28, fluid pressure will build up in the lower portion of the cylinder 25 and the intensifier will be actuated in the same manner previously described in connection with the downward stroke of the piston 2S. At the end of the upward stroke of piston 23, the latter will come to a halt and the pump l will move to neutral or substantially no delivery position until the valve 2d is reversed.

The operation of the circuit shown in Figure 2 is substantially the same as that described in connection with Figure l, the only exception being that the valve is not hydraulically shifted but is electrically shifted by means of the solenoids ist and 5l, the circuits of which are closed by actuation of the switches di and 58 by means of arm dil connected to the piston rod i8.

As long as no pressure is built up in the cylinder 2li, nuid delivered by pump l passes through conduit 'do and check valve El to the four-way valve 2li, but as soon as pressure is built up in the cylinder 26 and, therefore, also in conduit 23, this pressure closes the check valve di and, passing through pilot line S2, causes valve 5l to effect hydraulic communication between conduits 58 and 5E. The operation of the system of Figure 2 will then be carried out similar to that of Figure 1.

it will be understood that we desire to comprehend within our invention such modifications as come within the scope of the claims.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In an intensifier system, two cylinders, two synchronically movable diierential pistons respectively reciprocable in said cylinders, means for connecting said pistons with each other, each of said pistons having a large and an opposed smaller piston area, means for supplying uid to one of said smaller piston areas, and means for supplying pressure iiuid to the other smaller piston area and substantially simultaneously to one of said larger piston areas for imparting upon the fluid adjacent said first mentioned smaller piston area an intensified pressure corresponding to the ratio of said last mentioned smaller area to the total of the other smaller piston area and the large piston area acted upon by pressure iiuid.

2. In an intensier system, a pair of intensifier cylinders, each of said cylinders having reciprocably mounted therein a piston with a large and an opposed smaller differential piston area, means for operatively interconnecting said pistons, first valve means for selectively supplying The pump l will l ly directed differential pistons, each having a large piston area and an opposed smaller piston area, means positively interconnecting said pistons, valve means for controlling the supply of pressure iiuid to said piston areas, means for simultaneously supplying pressure fluid to the larger piston area of one piston and the smaller piston area of another piston to impart an increased pressure on the fluid adjacent the smaller area of said first mentioned piston, and means controlled by said pistons for controlling said valve means.

4. In a hydraulic system, two spaced oppositely directed intensifier pistons, each having a large and a smaller piston area, said pistons being rigidly connected with each other and being reciprocable in two separate cylinders, inlet and outlet means adjacent the inner ends of said intensier cylinders, a pressure fluid source adapted to supply pressure fluid to said areas, valve means interposed between said pressure fluid source and said intensifier cylinders and operable to admit pressure fluid simultaneously to the large piston area of one piston and the smaller piston area of the other piston, to thereby impart intensified pressure on fluid adjacent the other smaller piston area, and means operable by said intensifier pistons for controlling said valve means.

5. In an intensifier system, a pair of cylinders, a pair of fluid operable pistons reciprocable in said cylinders, each piston having a large and an opposed smaller piston area, means positively interconnecting said pistons, a fluid source for supplying pressure fluid to said piston areas, a fluid operable valve hydraulically connected with said cylinders and operable to selectively convey pressure fluid from said fluid source to the large piston area of one piston and simultaneously to the smaller piston area of the other piston, means responsive to the Abuilding up of pressure at the pressure side of said fluid source for automatically initiating operation of said diierential pistons, and means responsive to the travel vof said differential pistons for controlling said valve means.

6. In an intensifier system, a pair of oppositely directed differential pistons with the smaller piston areas directed toward each other and with the larger piston areas directed away from each other, two spaced intensifier cylinders having reciprocably mounted therein said pistons, a pressure liud source for supplying pressure fluid selectively to the larger piston area of one piston and simultaneously to the smaller piston area of the other piston, or to the larger area of said last mentioned piston and simultaneously to the smaller area of said first mentioned piston, valve means: interposed between said pressure fluid source and said cylinders for controlling the supply of pressure fluid to said piston areas, and a control valve operable by said pistons and in response to the establishment of a predetermined pressure at the pressure side of said fluid source for controlling the position of said valve means.

7. In an intensifier system, two synchronic'ally movable oppositely directed diierential pistons, each having a large and an opposed smaller area, a pressure iluid source for supplying pressure fluid to said pistons, a fluid operable valve for controlling the supply of pressure fluid from said fluid source to said pistons so as to admit pres-v sure fluid simultaneously to the larger piston area of on'e piston and the smaller piston are'a 

